FIG. 1 is an illustration of a wireless communication system where all the users are handled by a radio network controller (RNC) 20. Each user, wireless transmit/receive unit (WTRU) 24, wirelessly communicates with a Node-B 221. A group of Node-Bs 221-222 are controlled by the radio network controller (RNC) 20.
As the WTRU 24 moves, the WTRU 241, 242 is handed off between base stations/Node-Bs 32, 34. FIG. 2 is an illustration of a WTRU 241, 242 moving from an area handled by a first RNC 28 to an area handled by a second RNC 26. The WTRU 242 is considered to have “drifted” into the new RNC's region and that RNC (the second RNC) is considered the drift RNC (D-RNC) 26. The D-RNC 26 has Node-Bs 32, which it controls. The first RNC is referred to as the servicing RNC (S-RNC) 28. Typically, the RNCs (S-RNC 28 and D-RNC 26) can communicate some information to each other over a RNC interface (Iur). After the WTRU 242 “drifts” to the D-RNC 26, the D-RNC 26 performs functions, such as dynamic channel allocation (DCA), admission control, scheduling and RRM functions for the “drifting” WTRU 242. The S-RNC 28 still performs other functions for the “drifting” WTRU 242, such as handoff decisions and collecting of WTRU downlink measurements. When the WTRU 24 has not “drifted”, such as in FIG. 1, the RNC 20 handling the WTRU 24 performs the functions of both the S-RNC 28 and D-RNC 26.
Under the R99, R4 and R5 Iur specifications as proposed for the third generation partnership project (3GPP), when the WTRU 241, 242 is handed over from the S-RNC 28 to the D-RNC 26, cell loading and many Node-B measurements are sent from the S-RNC 28 to the D-RNC 26. However, there is no mechanism to transfer certain information from the S-RNC 28 to the D-RNC 26, such as the WTRU measurements.
Accordingly, it is desirable to have better peer-to-peer communications between RNCs.